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Barghouth M, Ye Y, Karagiannopoulos A, Ma Y, Cowan E, Wu R, Eliasson L, Renström E, Luan C, Zhang E. The T-type calcium channel Ca V3.2 regulates insulin secretion in the pancreatic β-cell. Cell Calcium 2022; 108:102669. [PMID: 36347081 DOI: 10.1016/j.ceca.2022.102669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 11/08/2022]
Abstract
Voltage-gated Ca2+ (CaV) channel dysfunction leads to impaired glucose-stimulated insulin secretion in pancreatic β-cells and contributes to the development of type-2 diabetes (T2D). The role of the low-voltage gated T-type CaV channels in β-cells remains obscure. Here we have measured the global expression of T-type CaV3.2 channels in human islets and found that gene expression of CACNA1H, encoding CaV3.2, is negatively correlated with HbA1c in human donors, and positively correlated with islet insulin gene expression as well as secretion capacity in isolated human islets. Silencing or pharmacological blockade of CaV3.2 attenuates glucose-stimulated cytosolic Ca2+ signaling, membrane potential, and insulin release. Moreover, the endoplasmic reticulum (ER) Ca2+ store depletion is also impaired in CaV3.2-silenced β-cells. The linkage between T-type (CaV3.2) and L-type CaV channels is further identified by the finding that the intracellular Ca2+ signaling conducted by CaV3.2 is highly dependent on the activation of L-type CaV channels. In addition, CACNA1H expression is significantly associated with the islet predominant L-type CACNA1C (CaV1.2) and CACNA1D (CaV1.3) genes in human pancreatic islets. In conclusion, our data suggest the essential functions of the T-type CaV3.2 subunit as a mediator of β-cell Ca2+ signaling and membrane potential needed for insulin secretion, and in connection with L-type CaV channels.
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Affiliation(s)
- Mohammad Barghouth
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden
| | - Yingying Ye
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden.
| | - Alexandros Karagiannopoulos
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö 20502, Sweden
| | - Yunhan Ma
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden
| | - Elaine Cowan
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö 20502, Sweden
| | - Rui Wu
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden; NanoLund, Lund University, P.O. Box 118, Lund 22100, Sweden
| | - Lena Eliasson
- Unit of Islet Cell Exocytosis, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö 20502, Sweden
| | - Erik Renström
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden
| | - Cheng Luan
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden.
| | - Enming Zhang
- Unit of Islet Pathophysiology, Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Lund University, Malmö, 20502, Sweden; NanoLund, Lund University, P.O. Box 118, Lund 22100, Sweden.
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